In general, systems have been developed incorporating dual (or a greater number of) displays. Some of these systems have plural displays with each display exhibiting identical information, such as in the case of plural CRT monitors coupled to a common signal source.
In performing text editing operations it is desirable to clearly delineate portions of text to be deleted or replaced. The problem of clearly delineating such information is compounded in systems having plural displays. This is because the information to be deleted or replaced must be clearly delineated in two displays. Moreover, the problem is further compounded where the plural displays are of different types having different capabilities such as a CRT display and gas plasma display. These displays and, in particularly the gas plasma display, have limitations as to the particular characters that can be exhibited. In one gas plasma display, the dot matrix is seven by approximately 220 dots, each of which can be illuminated. This provides a limitation as to particular characters that can be exhibited and the manner in which the characters can be marked when they are to be deleted or replaced.
Typical cursor systems are shown in U.S. Pat. No. 3,810,107 granted to Goldman et al, U.S. Pat. No. 3,828,316 granted to Card et al, and U.S. Pat. No. 4,190,835 granted to Buynak. The systems disclosed in these references are designed to provide cursors for a CRT display, but they are structured and operate in a manner which does not provide the capability required for cursor control for plural display on systems.
The Goldman et al reference discloses an electronic text display and processing system in which the text indexing functions are accomplished by means of a processor receiving commands indicative of operator action as well as commands indicative of internal signals generated in proper time sequence to perform the functions selected by the operator. Multiplexing and data selection means are provided for sequentially reconfiguring the flow of information through the various storage means within the memory to accomplish the text editing function.
The Card et al reference discloses a programmable system for selecting characters in a word-oriented computer system. The character addressing system also provides control circuitry for sequentially incrementing or decrementing successive characters whereby sequences of characters can be manipulated by the computer system.
The Buynak reference discloses a display with dual cursors: the first indicating the row and column in the display selected by the user, the second "shadow" cursor appearing in the same column but on the rule indice line of the display.